Lloyd’s Register (LR) has hosted what it calls the world’s first workshop on full scale hydrodynamic computer simulations at their Global Technology Centre in Southampton. Ship designers from around the world came together with the aim of building confidence in the accuracy of ship scale Computational Fluid Dynamics (CFD) modeling within the marine sector, according to LR.
The classification society said that this is the first time that the industry has openly compared full scale CFD with comprehensive measurements. Through comparisons of blind simulation results submitted by participants, and the speed trials carried out, the workshop demonstrated that ship speed could be predicted within approximately 4 percent of actual trial speeds.
The workshop is seen as step on the path to making CFD the final verification of ship scale design performance, rather than relying on scale model tests, according to LR. The transition to this approach will help reduce design costs and provide a greater opportunity to develop more energy efficient ship designs.
Participants from 15 countries provided details of their CFD modeling and discussed the reasons for any differences to help develop industry guidance for ship scale CFD modeling. The objective is to increase the accuracy of ship scale CFD and help make CFD a primary ship performance and design tool for the marine industry.
The subject ship of the workshop was a 16.9k DWT general cargo vessel described to have a simple geometrical configuration: single screw, no thrusters, no bulbous bow, and no energy saving devices.
The participants blind simulation results were compared as part of the following four modeling scenarios: ship scale resistance simulation (4 speeds), ship scale propeller open water characteristics computations (5 speeds), ship scale self-propulsion simulation (3 speeds) and ship scale propeller cavitation (1 condition).
LR’s Innovation Strategy and Research Director Luis Benito commented: "In the era of 'simulation', CFD technology and advanced computing power play key roles in predicting performance ahead of reality. We have engaged world experts by sharing measured performance data from an operating ship and facilitating a discussion of the different CFD modeling approaches used by the participants. This meeting has created a community among industry and helped to further enhance LR's own CFD modeling expertise. LR CFD in turn can predict reality on aspects of ship performance.”